A. Field
The invention relates to apparatus used in the die necking of aluminum beverage cans. More particularly, this invention relates to a flexible arrangement of necking stations for necking the open end of a can body, in which the can body has a diameter greater than 2.8 inches. Such cans are used for holding larger volumes of beverage such as for example 20 or 24 fluid ounces.
B. Related Art
Conventional aluminum beverage cans are made from an aluminum alloy disc which is drawn into a cup and then subject to further drawing and ironing into a can body by a device known as a can body maker. The can body has a sidewall, composed of a mid-wall portion and a top wall portion, and an integral bottom wall. In the drawing and ironing process, the bottom of the can is typically formed into a central inwardly-directed dome configuration and a peripheral, lowermost annular rim (sometimes referred to as a “stand” or “nose radius”) which forms the structure supporting the can when the can is placed upright on a horizontal surface. Can body makers, including punch sleeves and related tooling for forming a can body are known in the art and commercially available, see for example U.S. Pat. No. 6,434,996, the content of which is incorporated by reference herein. See also U.S. Pat. Nos. 4,852,377; 3,735,629; 5,394,727; 5,014,536 and 4,414,836, also incorporated by reference herein.
The can thus formed is then sent to a necking unit having a plurality of stations in which the top wall is subject to a plurality of necking steps, in which the diameter of the open end of the can is progressively reduced. After necking, a flange is formed on the open end for receiving a separate closure member or end.
Necking units use a multitude of individual, progressive necking stations, each one progressively reducing the diameter of the neck a bit more than the diameter produced from the previous necking station. Necking units are commercially available and described in the patent literature, see for example U.S. Pat. Nos. 5,775,161; 4,774,839; 5,775,130 and 6,698,265. The description of the necking units and individual necking modules (stations) of these patents is incorporated by reference herein.
This disclosure relates to a set of necking stations used to neck a relatively large size diameter beverage can (one with a diameter prior to necking of at least 2.8 inches, such as for example 3.0 inches or larger) in which the set of necking stations can be used to neck the can down to a first diameter for receiving a first standard end such as a 202 (2 and 2/16ths inches) end, and in which a subset of the necking stations can be used to neck the can down to receive a second standard diameter end such as a 206 (2 and 6/16ths inches) end or a 209 (2 and 9/16ths) diameter end. This feature provides the flexibility of the can manufacturer to change the necking of the can body to adapt to different end requirements for its customers, without having to invest in creation of separate tooling. For example, where customer A desires to use the larger size can and have a small end (e.g., 202 end), a subset of the necking stations created for manufacturing such an end can also be used if the customer (or a different customer, customer B) wants to use the same basic large size can but have a larger end (e.g., a 209 end). This invention also relates to a punch sleeve for a can body maker which is modified to provide a longer top wall in order to allow such a larger diameter can to be necked to smaller diameter sizes.